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This Article Full Text Full Text (PDF) All Versions of this Article: 567/2/583    most recent jphysiol.2005.087031v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Nordsborg, N. Articles by Bangsbo, J. Search for Related Content PubMed PubMed Citation Articles by Nordsborg, N. Articles by Bangsbo, J.

¹ August Krogh Institute, Institute of Exercise and Sport Sciences, Universitetsparken 13, 2100 Copenhagen, Denmark
² School of Human Movement, Recreation and Performance, Victoria University of Technology, PO Box 14428, Melbourne, Australia

Dexamethasone, a widely clinically used glucocorticoid, increases human skeletal muscle Na⁺,K⁺ pump content, but the effects on maximal Na⁺,K⁺ pump activity and subunit specific mRNA are unknown. Ten healthy male subjects ingested dexamethasone for 5 days and the effects on Na⁺,K⁺ pump content, maximal activity and subunit specific mRNA level (1, 2, ß1, ß2, ß3) in deltoid and vastus lateralis muscle were investigated. Before treatment, maximal Na⁺,K⁺ pump activity, as well as 1, 2, ß1 and ß2 mRNA levels were higher (P < 0.05) in vastus lateralis than in deltoid. Dexamethasone treatment increased Na⁺,K⁺ pump maximal activity in vastus lateralis and deltoid by 14 ± 7% (P < 0.05) and 18 ± 6% (P < 0.05) as well as Na⁺,K⁺ pump content by 18 ± 9% (P < 0.001) and 24 ± 8% (P < 0.01), respectively. Treatment with dexamethasone resulted in a higher 1, 2, ß1 and ß2 mRNA expression in the deltoid (P < 0.05), but no effects on Na⁺,K⁺ pump mRNA were detected in vastus lateralis. In conclusion, dexamethasone treatment increased maximal Na⁺,K⁺ pump activity in both vastus lateralis and deltoid muscles. The relative importance of transcription and translation in the glucocorticoid-induced regulation of Na⁺,K⁺ pump expression seems to be muscle specific and possibly dependent on the actual training condition of the muscle, such that a high Na⁺,K⁺ pump maximal activity and mRNA level prior to treatment prevents the transcriptional response to dexamethasone, but not the increase in Na⁺,K⁺ pump content and maximal activity.

(Received 21 March 2005; accepted after revision 20 June 2005; first published online 23 June 2005)
Corresponding author J. Bangsbo: August Krogh Institute, Institute of Exercise and Sport Sciences, Universitetsparken 13, 2. floor, 2100 Copenhagen, Denmark.  Email: jbangsbo{at}aki.ku.dk

This article has been cited by other articles:

				N. Nordsborg, J. Ovesen, M. Thomassen, M. Zangenberg, C. Jons, F. M. Iaia, J. J. Nielsen, and J. Bangsbo Effect of dexamethasone on skeletal muscle Na+,K+ pump subunit specific expression and K+ homeostasis during exercise in humans J. Physiol., March 1, 2008; 586(5): 1447 - 1459. [Abstract] [Full Text] [PDF]